This invention relates to check valves and provides a check valve particularly adaptable to a low pressure water pumping system transferring water from an underground well to the ground surface for household or light commercial use.
Check valves of numerous types and varied application are well known. A particularly useful application is the insertion of such valves in water well systems to check the water flow and prevent backflow from a water tank or reservoir back into the well. Such check valves preferably exhibit good flow and pressure loss characteristics as is necessary for effective use on suction lines of shallow well jet or reciprocating pumps, on discharge lines of submersible pumps and in lines running between the pump and tank of deep well reciprocating pumps.
Check valves used in such applications often include components and design features which can result in sticking of the valve due to a buildup of debris from the pumped water, and which also can result in excessive wear of the components providing undesirable leakage, replacement requirements, and a limited life. Relatively high pressure drops are not uncommon. Many of the valve designs have numerous components, and include sacrificial O-rings and other seals, which also limit the operating life. Check valves in operation are often not readily repairable in the field, and require removal from the operating location for repair or parts replacement.
Exemplary of check valves which are particularly adaptable to water wells are those disclosed in U.S. Pat. No's 3,209,777 and 1,568,940.
While check valves have long been operating in water well applications, improvements can be made. It is particularly desirable to provide check valves with good pressure and flow characteristics, a limited number of parts, the capability for long life and yet ease of parts replacement, particularly remotely, and a limited possibility of sticking or related malfunctions.